Keep in mind:
most (if not all) settings are LIMITS for the generator to use, NOT exact measurements.
work in small increments - sometimes a change of 0.01 on some settings will make a MAJOR change in the look of a map.
some settings will effect the results of other settings...
i recommend starting in solo mode with low settings, then adjust your map one setting at a time until you know how each setting effects your resulting map. This way if you see strange results yo